Jews and Gentiles relationship/obligation to the law prior to Jesus

If you could write a 1-2 paragraph explanation to someone explaining in your own words the Jews and Gentiles relationship/obligation to the law before Christ and after what would you say. I know your busy so whenever you get a chance. 

Ex 19-24 the Law was a covenant between God and the Nation of Israel.  According to Lev. 26 and Deut. 28 the Law was the basis of their blessings or cursings.

Since the Gentiles were cut off from God and according to Eph. 2:11,12 were strangers from the covenants of promise, the law had nothing to do with the Gentiles.

The New Covenant will be the means Israel will be able to keep God’s laws and finally be blessed with all God’s promises and will reign with Christ.  The Gentiles will then be invited into Christ’s Kingdom and God’s laws will flow to the Gentiles (Isaiah 2).  God’s law will be the law of the Kingdom (Matthew 5-7). 

Sorry Tom, I should have clarified more. I understand all that you had mentioned. I guess what I was looking for is the Gentiles relationship to the law and how you would explain it in regards to before the law was given to Israel(Romans 2:14) and after the law was given to Israel. Whenever you get a chance. Thanks as always!

Before the law was given to Israel the law seems to be known by early man (including the nations before there was an Israel).  The Sabbath is mentioned from the beginning although not spoken of again until given to Israel as the sign of the covenant of law.  Noah was told to take 7 of the clean animals and he knew which were clean.  Then there was Melchizedek who was the priest of the most high God.  So they had priests and sacrifices.  Also Abraham gave him a tithe, so they knew something about tithing.

After the law was given to Israel, the Gentiles were cut off from God and the law had no bearing on them.